From 850ea57c37e517eb0f10d8fc319332ca339d0ba2 Mon Sep 17 00:00:00 2001
From: antirez <antirez@gmail.com>
Date: Fri, 10 Oct 2014 17:44:06 +0200
Subject: [PATCH] rio.c: draft implementation of fdset target implemented.

---
 src/rio.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/rio.h |  9 +++++++++
 2 files changed, 69 insertions(+)

diff --git a/src/rio.c b/src/rio.c
index aa5061b7..88f6781e 100644
--- a/src/rio.c
+++ b/src/rio.c
@@ -142,6 +142,66 @@ void rioInitWithFile(rio *r, FILE *fp) {
     r->io.file.autosync = 0;
 }
 
+/* ------------------- File descriptors set implementation ------------------- */
+
+/* Returns 1 or 0 for success/failure. */
+static size_t rioFdsetWrite(rio *r, const void *buf, size_t len) {
+    size_t retval;
+    int j;
+    unsigned char *p = (unsigned char*) buf;
+
+    /* Write in little chunchs so that when there are big writes we
+     * parallelize while the kernel is sending data in background to
+     * the TCP socket. */
+    while(len) {
+        size_t count = len < 1024 ? len : 1024;
+        for (j = 0; j < r->io.fdset.numfds; j++) {
+            retval = write(r->io.fdset.fds[j],p,count);
+            if (retval != count) return 0;
+        }
+        p += count;
+        len -= count;
+        r->io.fdset.pos += count;
+    }
+    return 1;
+}
+
+/* Returns 1 or 0 for success/failure. */
+static size_t rioFdsetRead(rio *r, void *buf, size_t len) {
+    REDIS_NOTUSED(r);
+    REDIS_NOTUSED(buf);
+    REDIS_NOTUSED(len);
+    return 0; /* Error, this target does not support reading. */
+}
+
+/* Returns read/write position in file. */
+static off_t rioFdsetTell(rio *r) {
+    return r->io.fdset.pos;
+}
+
+static const rio rioFdsetIO = {
+    rioFdsetRead,
+    rioFdsetWrite,
+    rioFdsetTell,
+    NULL,           /* update_checksum */
+    0,              /* current checksum */
+    0,              /* bytes read or written */
+    0,              /* read/write chunk size */
+    { { NULL, 0 } } /* union for io-specific vars */
+};
+
+void rioInitWithFdset(rio *r, int *fds, int numfds) {
+    *r = rioFdsetIO;
+    r->io.fdset.fds = zmalloc(sizeof(int)*numfds);
+    memcpy(r->io.fdset.fds,fds,sizeof(int)*numfds);
+    r->io.fdset.numfds = numfds;
+    r->io.fdset.pos = 0;
+}
+
+void rioFreeFdset(rio *r) {
+    zfree(r->io.fdset.fds);
+}
+
 /* ---------------------------- Generic functions ---------------------------- */
 
 /* This function can be installed both in memory and file streams when checksum
diff --git a/src/rio.h b/src/rio.h
index 2d12c6cc..0d485d45 100644
--- a/src/rio.h
+++ b/src/rio.h
@@ -61,15 +61,23 @@ struct _rio {
 
     /* Backend-specific vars. */
     union {
+        /* In-memory buffer target. */
         struct {
             sds ptr;
             off_t pos;
         } buffer;
+        /* Stdio file pointer target. */
         struct {
             FILE *fp;
             off_t buffered; /* Bytes written since last fsync. */
             off_t autosync; /* fsync after 'autosync' bytes written. */
         } file;
+        /* Multiple FDs target (used to write to N sockets). */
+        struct {
+            int *fds;
+            int numfds;
+            off_t pos;
+        } fdset;
     } io;
 };
 
@@ -111,6 +119,7 @@ static inline off_t rioTell(rio *r) {
 
 void rioInitWithFile(rio *r, FILE *fp);
 void rioInitWithBuffer(rio *r, sds s);
+void rioInitWithFdset(rio *r, int *fds, int numfds);
 
 size_t rioWriteBulkCount(rio *r, char prefix, int count);
 size_t rioWriteBulkString(rio *r, const char *buf, size_t len);